Duet power catamaran launched

[Dinis Matias]

Duet is a very modified Skoota 36 power catamaran, was launched October 2023 in Steveston, BC, Canada.
I invite you to see her here : https://www.youtube.com/channel/UCWozWL ... TvD4MnneSA
I appreciated any comments.
Dinis

[cape man]

What an awesome job! Beautiful!

[cape man]

Did you add the bulbous bows after first launch?

[Dinis Matias]

The bulbous bows were added after I done a dip test early in the year and find out that I was down by the bow 10 inches.
The design has a LCB 1.250 m aft of the LCG and the designer told me he does that because the majority of builder put more weight aft.
I don't agree.

[Fuzz]

Just beautiful work all the way around! What kind of cruising speed do you get?
I note you had the same bow down problem Fallguy did

[Dinis Matias]

Early this year when I done a dip test, we done 14.4kn at 4850 rpm with a 14x11 propelers.
This time around the maximum speed that we achived was 13.4kn at 5650 rpm with a 14x9 propelers, with 4 adults and more the half load.

This time around my speed is;

3000 rpm 1 gph 6.5 kn
4000 rpm 2 gph 9 kn
5000 rpm 3.3 gph 10 kn
5650 rpm 5.1 gph 13.4 kn
Off course this speeds are with 2 engines.

As you can see, I lost 1kn, I suspect because of the increased wetted surface with the BB's and spoosons, althought I have now a longer WL
Because my speed is directly propotional to the price at the pump, my crusing speed is 6.5 kn a magic carpet ride.

[Dinis Matias]

Fallguy and I share the same problem and we are not the only ones

[narfi]

Very nice. You spent some time on it this last summer?

[fallguy1000]

The bulbous bows were added after I done a dip test early in the year and find out that I was down by the bow 10 inches.
The design has a LCB 1.250 m aft of the LCG and the designer told me he does that because the majority of builder put more weight aft.
I don't agree.

baloney is a sandwich meat

The truth is Richard went to the Wharram school of design which is try again until it is right.

His designs are overly minimalistic.

I don't have any animosity for the man; his boats look pretty great and he did the build drawings I needed.

But LCB and LCG must be equal or the boat will not trim properly. That is simple boats 101. Richard did NOT weight study these and the Skootas are not quite right. A weight study of the GA is essential and the boats do not have proper hydrostatics.

I was also warned by another engineer that my boat must not run anywhere near full speed in seas above one meter which means the boat is Class C; not B. In fact, we told to stay below 10knots in anything over a meter. This is based on the composite schedule which needed to be beefier, which would add weight.

The bottom line is the bows are not full enough and the Skoota designs need wider hulls. The tradeoff of less fuel economy is in the noise.

I would be less vocal, but I asked Richard to address the issues and he did not seem to be interested.

Thank heavens for the help from Ad Hoc Marine Designs in Japan.

[Dinis Matias]

narfi, I launched October, this year and she is a of marinas full time liveaboard.